1. Field of the Invention
The present invention relates to a signal acquisition apparatus and method and a signal transmission apparatus and method.
2. Description of the Prior Art
A number of Digital Video Broadcasting (DVB) standards have been proposed in recent times, such as DVB-T (terrestrial), DVB-T2 (2nd generation terrestrial), DVB-H (handheld, or mobile), DVB-S2 (satellite) and DVB-C2 (cable).
The different standards address different requirements specific to each kind of transmission/reception, such as terrestrial broadcasts, or broadcasts to handheld devices.
In the case of hand-held devices, both cost and power consumption are significant factors. Consequently a mobile device may only have one tuner available for receiving DVB signals.
In the case of a DVB signal adhering to a mobile standard in which the signal is intermittent and optionally also hops between different frequencies, this introduces the need to acquire the signal anew with each intermittent transmission.
Moreover, some DVB standards use orthogonal frequency division multiplexing, which requires certain information to be available to a receiver before any video data can be obtained from the remaining signal. This information is sometimes provided at the start of a transmitted data frame, for example in DVB-T2.
Consequently if a mobile device cannot acquire the DVB signal quickly enough to obtain this information, the rest of the data frame and the video information it contains remains inaccessible, resulting in reduced image quality.
Some DVB standards attempt to mitigate this problem by encoding this initial information in a robust manner that enables comparatively easy acquisition, but there is clear scope to improve upon this arrangement.